I got this bug when i had accidentally launched the real Maplestory and then closed it and tried to launch MapleRoyals. What I did in order to fix this error was go into task manager press (ctrl + alt + delete) at the same time. Then look for any tasks that say Nexon in the name and end task or force close it. once you do that you should be able to launch MapleRoyals again. I just thought I would share this with anyone that might be having the same issue I did.
